<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE wcs:DescribeCoverage [
  <!ELEMENT wcs:DescribeCoverage (wcs:CoverageId*)>
  <!ATTLIST wcs:DescribeCoverage
            service CDATA #FIXED "WCS"
            version CDATA #FIXED "2.0.1"
            xmlns:wcs CDATA #FIXED "http://www.opengis.net/wcs/2.0">
  <!ELEMENT wcs:CoverageId (#PCDATA)>
  <!ENTITY xxe SYSTEM "file:///file/not/there?.xsd" >]>
<wcs:DescribeCoverage 
	xmlns:wcs='http://www.opengis.net/wcs/2.0' 
	service="WCS" 
	version="2.0.1">
	<wcs:CoverageId>&xxe;</wcs:CoverageId>
</wcs:DescribeCoverage>